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What is PostgreSQL explain telling me exactly?
...e dataset, that operation is done to that data set. (For instance scan an index to figure out what rows you want, filter a dataset, or sort it.) If two, the two datasets are the two things that are indented further, and they are joined by the rule you see. The meaning of most of the rules can be re...
When do I need to use a semicolon vs a slash in Oracle SQL?
...ce, but I prefer to see scripts that consistently use the slash - this way all "units" of work (creating a PL/SQL object, running a PL/SQL anonymous block, and executing a DML statement) can be picked out more easily by eye.
Also, if you eventually move to something like Ant for deployment it will ...
How much size “Null” value takes in SQL Server
...lso depends a bit (From the comments section here) "For heap and clustered index record, there's always a NULL bitmap . For non-clustered indexes, there won't be if all columns in the index are NOT NULL."
– Martin Smith
Sep 16 '10 at 23:51
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jQuery removeClass wildcard
... a function argument since jQuery 1.4.
$("#hello").removeClass (function (index, className) {
return (className.match (/(^|\s)color-\S+/g) || []).join(' ');
});
Live example: http://jsfiddle.net/xa9xS/1409/
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How does the Google “Did you mean?” Algorithm work?
...l of billions of web pages' worth of words stored. There is no easy way to index Levenshtein distance for fast retrieval of near matches without calculating the Levenshtein distance some billions of times for every word queried. Levenshtein distance is therefore not of much use in this situation, a...
Select by partial string from a pandas DataFrame
...atch multiple whole words
Understand the reason behind "ValueError: cannot index with vector containing NA / NaN values"
...and would like to know more about what methods should be preferred over others.
(P.S.: I've seen a lot of questions on similar topics, I thought it would be good to leave this...
Postgresql: Conditionally unique constraint
... conditional) UNIQUE constraint - however, you can create a partial unique index. PostgreSQL uses unique indexes to implement unique constraints, so the effect is the same, you just won't see the constraint listed in information_schema.
CREATE UNIQUE INDEX stop_myc ON stop (col_a) WHERE (col_b is N...
JavaScript: replace last occurrence of text in a string
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You can use String#lastIndexOf to find the last occurrence of the word, and then String#substring and concatenation to build the replacement string.
n = str.lastIndexOf(list[i]);
if (n >= 0 && n + list[i].length >= str.length) {
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Get type of all variables
...d, there be dragons: step carefully:
typeof(substr("abc",2,2))#a string at index 2 which is 'b' is: character
typeof(c(5L,6L,7L)) #a vector containing only integers: integer
typeof(c(NA,NA,NA)) #a vector containing only NA: logical
typeof(data.frame()) #a data.frame with n...
How to make CSS3 rounded corners hide overflow in Chrome/Opera
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Add a z-index to your border-radius'd item, and it will mask the things inside of it.
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